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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
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 * 2 along with this work; if not, write to the Free Software Foundation,
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 *
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package java.util;

/**
 * The <code>Vector</code> class implements a growable array of objects. Like an
 * array, it contains components that can be accessed using an integer index.
 * However, the size of a <code>Vector</code> can grow or shrink as needed to
 * accommodate adding and removing items after the <code>Vector</code> has been
 * created.<p>
 *
 * Each vector tries to optimize storage management by maintaining a
 * <code>capacity</code> and a <code>capacityIncrement</code>. The
 * <code>capacity</code> is always at least as large as the vector size; it is
 * usually larger because as components are added to the vector, the vector's
 * storage increases in chunks the size of <code>capacityIncrement</code>. An
 * application can increase the capacity of a vector before inserting a large
 * number of components; this reduces the amount of incremental reallocation.
 * <p>
 *
 * As of the Java 2 platform v1.2, this class has been retrofitted to implement
 * List, so that it becomes a part of Java's collection framework. Unlike the
 * new collection implementations, Vector is synchronized.<p>
 *
 * The Iterators returned by Vector's iterator and listIterator methods are
 * <em>fail-fast</em>: if the Vector is structurally modified at any time after
 * the Iterator is created, in any way except through the Iterator's own remove
 * or add methods, the Iterator will throw a ConcurrentModificationException.
 * Thus, in the face of concurrent modification, the Iterator fails quickly and
 * cleanly, rather than risking arbitrary, non-deterministic behavior at an
 * undetermined time in the future. The Enumerations returned by Vector's
 * elements method are <em>not</em>
 * fail-fast.
 *
 * <p>
 * Note that the fail-fast behavior of an iterator cannot be guaranteed as it
 * is, generally speaking, impossible to make any hard guarantees in the
 * presence of unsynchronized concurrent modification. Fail-fast iterators throw
 * <tt>ConcurrentModificationException</tt> on a best-effort basis. Therefore,
 * it would be wrong to write a program that depended on this exception for its
 * correctness:  <i>the fail-fast behavior of iterators should be used only to
 * detect bugs.</i><p>
 *
 * This class is a member of the
 * <a href="{@docRoot}/../guide/collections/index.html">
 * Java Collections Framework</a>.
 *
 * @author Lee Boynton
 * @author Jonathan Payne
 * @version 1.96, 02/19/04
 * @see Collection
 * @see List
 * @see ArrayList
 * @see LinkedList
 * @since JDK1.0
 */
public class Vector<E>
        extends AbstractList<E>
        implements List<E>, RandomAccess, Cloneable {

    /**
     * The array buffer into which the components of the vector are stored. The
     * capacity of the vector is the length of this array buffer, and is at
     * least large enough to contain all the vector's elements.<p>
     *
     * Any array elements following the last element in the Vector are null.
     *
     * @serial
     */
    protected Object[] elementData;

    /**
     * The number of valid components in this <tt>Vector</tt> object. Components
     * <tt>elementData[0]</tt> through
     * <tt>elementData[elementCount-1]</tt> are the actual items.
     *
     * @serial
     */
    protected int elementCount;

    /**
     * The amount by which the capacity of the vector is automatically
     * incremented when its size becomes greater than its capacity. If the
     * capacity increment is less than or equal to zero, the capacity of the
     * vector is doubled each time it needs to grow.
     *
     * @serial
     */
    protected int capacityIncrement;

    /**
     * use serialVersionUID from JDK 1.0.2 for interoperability
     */
    private static final long serialVersionUID = -2767605614048989439L;

    /**
     * Constructs an empty vector with the specified initial capacity and
     * capacity increment.
     *
     * @param initialCapacity the initial capacity of the vector.
     * @param capacityIncrement the amount by which the capacity is increased
     * when the vector overflows.
     * @exception IllegalArgumentException if the specified initial capacity is
     * negative
     */
    public Vector(int initialCapacity, int capacityIncrement) {
        super();
        if (initialCapacity < 0) {
            throw new IllegalArgumentException("Illegal Capacity: "
                    + initialCapacity);
        }
        this.elementData = new Object[initialCapacity];
        this.capacityIncrement = capacityIncrement;
    }

    /**
     * Constructs an empty vector with the specified initial capacity and with
     * its capacity increment equal to zero.
     *
     * @param initialCapacity the initial capacity of the vector.
     * @exception IllegalArgumentException if the specified initial capacity is
     * negative
     */
    public Vector(int initialCapacity) {
        this(initialCapacity, 0);
    }

    /**
     * Constructs an empty vector so that its internal data array has size
     * <tt>10</tt> and its standard capacity increment is zero.
     */
    public Vector() {
        this(10);
    }

    /**
     * Constructs a vector containing the elements of the specified collection,
     * in the order they are returned by the collection's iterator.
     *
     * @param c the collection whose elements are to be placed into this vector.
     * @throws NullPointerException if the specified collection is null.
     * @since 1.2
     */
    public Vector(Collection<? extends E> c) {
        elementCount = c.size();
        // 10% for growth
        elementData = new Object[(int) Math.min((elementCount * 110L) / 100, Integer.MAX_VALUE)];
        c.toArray(elementData);
    }

    /**
     * Copies the components of this vector into the specified array. The item
     * at index <tt>k</tt> in this vector is copied into component
     * <tt>k</tt> of <tt>anArray</tt>. The array must be big enough to hold all
     * the objects in this vector, else an
     * <tt>IndexOutOfBoundsException</tt> is thrown.
     *
     * @param anArray the array into which the components get copied.
     * @throws NullPointerException if the given array is null.
     */
    public synchronized void copyInto(Object[] anArray) {
        System.arraycopy(elementData, 0, anArray, 0, elementCount);
    }

    /**
     * Trims the capacity of this vector to be the vector's current size. If the
     * capacity of this vector is larger than its current size, then the
     * capacity is changed to equal the size by replacing its internal data
     * array, kept in the field <tt>elementData</tt>, with a smaller one. An
     * application can use this operation to minimize the storage of a vector.
     */
    public synchronized void trimToSize() {
        modCount++;
        int oldCapacity = elementData.length;
        if (elementCount < oldCapacity) {
            Object oldData[] = elementData;
            elementData = new Object[elementCount];
            System.arraycopy(oldData, 0, elementData, 0, elementCount);
        }
    }

    /**
     * Increases the capacity of this vector, if necessary, to ensure that it
     * can hold at least the number of components specified by the minimum
     * capacity argument.
     *
     * <p>
     * If the current capacity of this vector is less than
     * <tt>minCapacity</tt>, then its capacity is increased by replacing its
     * internal data array, kept in the field <tt>elementData</tt>, with a
     * larger one. The size of the new data array will be the old size plus
     * <tt>capacityIncrement</tt>, unless the value of
     * <tt>capacityIncrement</tt> is less than or equal to zero, in which case
     * the new capacity will be twice the old capacity; but if this new size is
     * still smaller than <tt>minCapacity</tt>, then the new capacity will be
     * <tt>minCapacity</tt>.
     *
     * @param minCapacity the desired minimum capacity.
     */
    public synchronized void ensureCapacity(int minCapacity) {
        modCount++;
        ensureCapacityHelper(minCapacity);
    }

    /**
     * This implements the unsynchronized semantics of ensureCapacity.
     * Synchronized methods in this class can internally call this method for
     * ensuring capacity without incurring the cost of an extra synchronization.
     *
     * @see java.util.Vector#ensureCapacity(int)
     */
    private void ensureCapacityHelper(int minCapacity) {
        int oldCapacity = elementData.length;
        if (minCapacity > oldCapacity) {
            Object[] oldData = elementData;
            int newCapacity = (capacityIncrement > 0)
                    ? (oldCapacity + capacityIncrement) : (oldCapacity * 2);
            if (newCapacity < minCapacity) {
                newCapacity = minCapacity;
            }
            elementData = new Object[newCapacity];
            System.arraycopy(oldData, 0, elementData, 0, elementCount);
        }
    }

    /**
     * Sets the size of this vector. If the new size is greater than the current
     * size, new <code>null</code> items are added to the end of the vector. If
     * the new size is less than the current size, all components at index
     * <code>newSize</code> and greater are discarded.
     *
     * @param newSize the new size of this vector.
     * @throws ArrayIndexOutOfBoundsException if new size is negative.
     */
    public synchronized void setSize(int newSize) {
        modCount++;
        if (newSize > elementCount) {
            ensureCapacityHelper(newSize);
        } else {
            for (int i = newSize; i < elementCount; i++) {
                elementData[i] = null;
            }
        }
        elementCount = newSize;
    }

    /**
     * Returns the current capacity of this vector.
     *
     * @return the current capacity (the length of its internal data array, kept
     * in the field <tt>elementData</tt>
     * of this vector).
     */
    public synchronized int capacity() {
        return elementData.length;
    }

    /**
     * Returns the number of components in this vector.
     *
     * @return the number of components in this vector.
     */
    public synchronized int size() {
        return elementCount;
    }

    /**
     * Tests if this vector has no components.
     *
     * @return  <code>true</code> if and only if this vector has no components,
     * that is, its size is zero; <code>false</code> otherwise.
     */
    public synchronized boolean isEmpty() {
        return elementCount == 0;
    }

    /**
     * Returns an enumeration of the components of this vector. The returned
     * <tt>Enumeration</tt> object will generate all items in this vector. The
     * first item generated is the item at index <tt>0</tt>, then the item at
     * index <tt>1</tt>, and so on.
     *
     * @return an enumeration of the components of this vector.
     * @see Enumeration
     * @see Iterator
     */
    public Enumeration<E> elements() {
        return new Enumeration<E>() {
            int count = 0;

            public boolean hasMoreElements() {
                return count < elementCount;
            }

            public E nextElement() {
                synchronized (Vector.this) {
                    if (count < elementCount) {
                        return (E) elementData[count++];
                    }
                }
                throw new NoSuchElementException("Vector Enumeration");
            }
        };
    }

    /**
     * Tests if the specified object is a component in this vector.
     *
     * @param elem an object.
     * @return  <code>true</code> if and only if the specified object is the same
     * as a component in this vector, as determined by the
     * <tt>equals</tt> method; <code>false</code> otherwise.
     */
    public boolean contains(Object elem) {
        return indexOf(elem, 0) >= 0;
    }

    /**
     * Searches for the first occurence of the given argument, testing for
     * equality using the <code>equals</code> method.
     *
     * @param elem an object.
     * @return the index of the first occurrence of the argument in this vector,
     * that is, the smallest value <tt>k</tt> such that
     * <tt>elem.equals(elementData[k])</tt> is <tt>true</tt>; returns
     * <code>-1</code> if the object is not found.
     * @see Object#equals(Object)
     */
    public int indexOf(Object elem) {
        return indexOf(elem, 0);
    }

    /**
     * Searches for the first occurence of the given argument, beginning the
     * search at <code>index</code>, and testing for equality using the
     * <code>equals</code> method.
     *
     * @param elem an object.
     * @param index the non-negative index to start searching from.
     * @return the index of the first occurrence of the object argument in this
     * vector at position <code>index</code> or later in the vector, that is,
     * the smallest value <tt>k</tt> such that
     * <tt>elem.equals(elementData[k]) && (k &gt;= index)</tt> is
     * <tt>true</tt>; returns <code>-1</code> if the object is not found.
     * (Returns <code>-1</code> if <tt>index</tt> &gt;= the current size of this
     * <tt>Vector</tt>.)
     * @exception IndexOutOfBoundsException if <tt>index</tt> is negative.
     * @see Object#equals(Object)
     */
    public synchronized int indexOf(Object elem, int index) {
        if (elem == null) {
            for (int i = index; i < elementCount; i++) {
                if (elementData[i] == null) {
                    return i;
                }
            }
        } else {
            for (int i = index; i < elementCount; i++) {
                if (elem.equals(elementData[i])) {
                    return i;
                }
            }
        }
        return -1;
    }

    /**
     * Returns the index of the last occurrence of the specified object in this
     * vector.
     *
     * @param elem the desired component.
     * @return the index of the last occurrence of the specified object in this
     * vector, that is, the largest value <tt>k</tt> such that
     * <tt>elem.equals(elementData[k])</tt> is <tt>true</tt>; returns
     * <code>-1</code> if the object is not found.
     */
    public synchronized int lastIndexOf(Object elem) {
        return lastIndexOf(elem, elementCount - 1);
    }

    /**
     * Searches backwards for the specified object, starting from the specified
     * index, and returns an index to it.
     *
     * @param elem the desired component.
     * @param index the index to start searching from.
     * @return the index of the last occurrence of the specified object in this
     * vector at position less than or equal to <code>index</code> in the
     * vector, that is, the largest value <tt>k</tt> such that
     * <tt>elem.equals(elementData[k]) && (k &lt;= index)</tt> is
     * <tt>true</tt>; <code>-1</code> if the object is not found. (Returns
     * <code>-1</code> if <tt>index</tt> is negative.)
     * @exception IndexOutOfBoundsException if <tt>index</tt> is greater than or
     * equal to the current size of this vector.
     */
    public synchronized int lastIndexOf(Object elem, int index) {
        if (index >= elementCount) {
            throw new IndexOutOfBoundsException(index + " >= " + elementCount);
        }

        if (elem == null) {
            for (int i = index; i >= 0; i--) {
                if (elementData[i] == null) {
                    return i;
                }
            }
        } else {
            for (int i = index; i >= 0; i--) {
                if (elem.equals(elementData[i])) {
                    return i;
                }
            }
        }
        return -1;
    }

    /**
     * Returns the component at the specified index.<p>
     *
     * This method is identical in functionality to the get method (which is
     * part of the List interface).
     *
     * @param index an index into this vector.
     * @return the component at the specified index.
     * @exception ArrayIndexOutOfBoundsException if the <tt>index</tt>
     * is negative or not less than the current size of this
     * <tt>Vector</tt> object. given.
     * @see	#get(int)
     * @see	List
     */
    public synchronized E elementAt(int index) {
        if (index >= elementCount) {
            throw new ArrayIndexOutOfBoundsException(index + " >= " + elementCount);
        }

        return (E) elementData[index];
    }

    /**
     * Returns the first component (the item at index <tt>0</tt>) of this
     * vector.
     *
     * @return the first component of this vector.
     * @exception NoSuchElementException if this vector has no components.
     */
    public synchronized E firstElement() {
        if (elementCount == 0) {
            throw new NoSuchElementException();
        }
        return (E) elementData[0];
    }

    /**
     * Returns the last component of the vector.
     *
     * @return the last component of the vector, i.e., the component at index
     * <code>size()&nbsp;-&nbsp;1</code>.
     * @exception NoSuchElementException if this vector is empty.
     */
    public synchronized E lastElement() {
        if (elementCount == 0) {
            throw new NoSuchElementException();
        }
        return (E) elementData[elementCount - 1];
    }

    /**
     * Sets the component at the specified <code>index</code> of this vector to
     * be the specified object. The previous component at that position is
     * discarded.<p>
     *
     * The index must be a value greater than or equal to <code>0</code> and
     * less than the current size of the vector.
     * <p>
     *
     * This method is identical in functionality to the set method (which is
     * part of the List interface). Note that the set method reverses the order
     * of the parameters, to more closely match array usage. Note also that the
     * set method returns the old value that was stored at the specified
     * position.
     *
     * @param obj what the component is to be set to.
     * @param index the specified index.
     * @exception ArrayIndexOutOfBoundsException if the index was invalid.
     * @see #size()
     * @see List
     * @see	#set(int, java.lang.Object)
     */
    public synchronized void setElementAt(E obj, int index) {
        if (index >= elementCount) {
            throw new ArrayIndexOutOfBoundsException(index + " >= "
                    + elementCount);
        }
        elementData[index] = obj;
    }

    /**
     * Deletes the component at the specified index. Each component in this
     * vector with an index greater or equal to the specified <code>index</code>
     * is shifted downward to have an index one smaller than the value it had
     * previously. The size of this vector is decreased by <tt>1</tt>.<p>
     *
     * The index must be a value greater than or equal to <code>0</code> and
     * less than the current size of the vector.
     * <p>
     *
     * This method is identical in functionality to the remove method (which is
     * part of the List interface). Note that the remove method returns the old
     * value that was stored at the specified position.
     *
     * @param index the index of the object to remove.
     * @exception ArrayIndexOutOfBoundsException if the index was invalid.
     * @see #size()
     * @see	#remove(int)
     * @see	List
     */
    public synchronized void removeElementAt(int index) {
        modCount++;
        if (index >= elementCount) {
            throw new ArrayIndexOutOfBoundsException(index + " >= "
                    + elementCount);
        } else if (index < 0) {
            throw new ArrayIndexOutOfBoundsException(index);
        }
        int j = elementCount - index - 1;
        if (j > 0) {
            System.arraycopy(elementData, index + 1, elementData, index, j);
        }
        elementCount--;
        elementData[elementCount] = null;
        /* to let gc do its work */
    }

    /**
     * Inserts the specified object as a component in this vector at the
     * specified <code>index</code>. Each component in this vector with an index
     * greater or equal to the specified <code>index</code> is shifted upward to
     * have an index one greater than the value it had previously.
     * <p>
     *
     * The index must be a value greater than or equal to <code>0</code> and
     * less than or equal to the current size of the vector. (If the index is
     * equal to the current size of the vector, the new element is appended to
     * the Vector.)
     * <p>
     *
     * This method is identical in functionality to the add(Object, int) method
     * (which is part of the List interface). Note that the add method reverses
     * the order of the parameters, to more closely match array usage.
     *
     * @param obj the component to insert.
     * @param index where to insert the new component.
     * @exception ArrayIndexOutOfBoundsException if the index was invalid.
     * @see #size()
     * @see	#add(int, Object)
     * @see	List
     */
    public synchronized void insertElementAt(E obj, int index) {
        modCount++;
        if (index > elementCount) {
            throw new ArrayIndexOutOfBoundsException(index
                    + " > " + elementCount);
        }
        ensureCapacityHelper(elementCount + 1);
        System.arraycopy(elementData, index, elementData, index + 1, elementCount - index);
        elementData[index] = obj;
        elementCount++;
    }

    /**
     * Adds the specified component to the end of this vector, increasing its
     * size by one. The capacity of this vector is increased if its size becomes
     * greater than its capacity.
     * <p>
     *
     * This method is identical in functionality to the add(Object) method
     * (which is part of the List interface).
     *
     * @param obj the component to be added.
     * @see	#add(Object)
     * @see	List
     */
    public synchronized void addElement(E obj) {
        modCount++;
        ensureCapacityHelper(elementCount + 1);
        elementData[elementCount++] = obj;
    }

    /**
     * Removes the first (lowest-indexed) occurrence of the argument from this
     * vector. If the object is found in this vector, each component in the
     * vector with an index greater or equal to the object's index is shifted
     * downward to have an index one smaller than the value it had
     * previously.<p>
     *
     * This method is identical in functionality to the remove(Object) method
     * (which is part of the List interface).
     *
     * @param obj the component to be removed.
     * @return  <code>true</code> if the argument was a component of this vector;
     * <code>false</code> otherwise.
     * @see	List#remove(Object)
     * @see	List
     */
    public synchronized boolean removeElement(Object obj) {
        modCount++;
        int i = indexOf(obj);
        if (i >= 0) {
            removeElementAt(i);
            return true;
        }
        return false;
    }

    /**
     * Removes all components from this vector and sets its size to zero.<p>
     *
     * This method is identical in functionality to the clear method (which is
     * part of the List interface).
     *
     * @see	#clear
     * @see	List
     */
    public synchronized void removeAllElements() {
        modCount++;
        // Let gc do its work
        for (int i = 0; i < elementCount; i++) {
            elementData[i] = null;
        }

        elementCount = 0;
    }

    /**
     * Returns a clone of this vector. The copy will contain a reference to a
     * clone of the internal data array, not a reference to the original
     * internal data array of this <tt>Vector</tt> object.
     *
     * @return a clone of this vector.
     */
    public synchronized Object clone() {
        try {
            Vector<E> v = (Vector<E>) super.clone();
            v.elementData = Arrays.copyOf(elementData, elementCount);
            v.modCount = 0;
            return v;
        } catch (Exception e) {
            // this shouldn't happen, since we are Cloneable
            e.printStackTrace();
            throw new RuntimeException(e);
        }
    }

    /**
     * Returns an array containing all of the elements in this Vector in the
     * correct order.
     *
     * @since 1.2
     */
    public synchronized Object[] toArray() {
        Object[] result = new Object[elementCount];
        System.arraycopy(elementData, 0, result, 0, elementCount);
        return result;
    }

    /**
     * Returns an array containing all of the elements in this Vector in the
     * correct order; the runtime type of the returned array is that of the
     * specified array. If the Vector fits in the specified array, it is
     * returned therein. Otherwise, a new array is allocated with the runtime
     * type of the specified array and the size of this Vector.<p>
     *
     * If the Vector fits in the specified array with room to spare (i.e., the
     * array has more elements than the Vector), the element in the array
     * immediately following the end of the Vector is set to null. This is
     * useful in determining the length of the Vector <em>only</em> if the
     * caller knows that the Vector does not contain any null elements.
     *
     * @param a the array into which the elements of the Vector are to be
     * stored, if it is big enough; otherwise, a new array of the same runtime
     * type is allocated for this purpose.
     * @return an array containing the elements of the Vector.
     * @exception ArrayStoreException the runtime type of a is not a supertype
     * of the runtime type of every element in this Vector.
     * @throws NullPointerException if the given array is null.
     * @since 1.2
     */
    public synchronized <T> T[] toArray(T[] a) {
        if (a.length < elementCount) 
            a = (T[])java.lang.reflect.Array.newInstance(
                                        a.getClass().getComponentType(), elementCount);

        System.arraycopy(elementData, 0, a, 0, elementCount);

        if (a.length > elementCount) {
            a[elementCount] = null;
        }

        return a;
    }

    // Positional Access Operations
    /**
     * Returns the element at the specified position in this Vector.
     *
     * @param index index of element to return.
     * @return object at the specified index
     * @exception ArrayIndexOutOfBoundsException index is out of range (index
     * &lt; 0 || index &gt;= size()).
     * @since 1.2
     */
    public synchronized E get(int index) {
        if (index >= elementCount) {
            throw new ArrayIndexOutOfBoundsException(index);
        }

        return (E) elementData[index];
    }

    /**
     * Replaces the element at the specified position in this Vector with the
     * specified element.
     *
     * @param index index of element to replace.
     * @param element element to be stored at the specified position.
     * @return the element previously at the specified position.
     * @exception ArrayIndexOutOfBoundsException index out of range (index &lt;
     * 0 || index &gt;= size()).
     * @since 1.2
     */
    public synchronized E set(int index, E element) {
        if (index >= elementCount) {
            throw new ArrayIndexOutOfBoundsException(index);
        }

        Object oldValue = elementData[index];
        elementData[index] = element;
        return (E) oldValue;
    }

    /**
     * Appends the specified element to the end of this Vector.
     *
     * @param o element to be appended to this Vector.
     * @return true (as per the general contract of Collection.add).
     * @since 1.2
     */
    public synchronized boolean add(E o) {
        modCount++;
        ensureCapacityHelper(elementCount + 1);
        elementData[elementCount++] = o;
        return true;
    }

    /**
     * Removes the first occurrence of the specified element in this Vector If
     * the Vector does not contain the element, it is unchanged. More formally,
     * removes the element with the lowest index i such that
     * <code>(o==null ? get(i)==null : o.equals(get(i)))</code> (if such an
     * element exists).
     *
     * @param o element to be removed from this Vector, if present.
     * @return true if the Vector contained the specified element.
     * @since 1.2
     */
    public boolean remove(Object o) {
        return removeElement(o);
    }

    /**
     * Inserts the specified element at the specified position in this Vector.
     * Shifts the element currently at that position (if any) and any subsequent
     * elements to the right (adds one to their indices).
     *
     * @param index index at which the specified element is to be inserted.
     * @param element element to be inserted.
     * @exception ArrayIndexOutOfBoundsException index is out of range (index
     * &lt; 0 || index &gt; size()).
     * @since 1.2
     */
    public void add(int index, E element) {
        insertElementAt(element, index);
    }

    /**
     * Removes the element at the specified position in this Vector. shifts any
     * subsequent elements to the left (subtracts one from their indices).
     * Returns the element that was removed from the Vector.
     *
     * @exception ArrayIndexOutOfBoundsException index out of range (index &lt;
     * 0 || index &gt;= size()).
     * @param index the index of the element to removed.
     * @return element that was removed
     * @since 1.2
     */
    public synchronized E remove(int index) {
        modCount++;
        if (index >= elementCount) {
            throw new ArrayIndexOutOfBoundsException(index);
        }
        Object oldValue = elementData[index];

        int numMoved = elementCount - index - 1;
        if (numMoved > 0) {
            System.arraycopy(elementData, index + 1, elementData, index,
                    numMoved);
        }
        elementData[--elementCount] = null; // Let gc do its work

        return (E) oldValue;
    }

    /**
     * Removes all of the elements from this Vector. The Vector will be empty
     * after this call returns (unless it throws an exception).
     *
     * @since 1.2
     */
    public void clear() {
        removeAllElements();
    }

    // Bulk Operations
    /**
     * Returns true if this Vector contains all of the elements in the specified
     * Collection.
     *
     * @param c a collection whose elements will be tested for containment in
     * this Vector
     * @return true if this Vector contains all of the elements in the specified
     * collection.
     * @throws NullPointerException if the specified collection is null.
     */
    public synchronized boolean containsAll(Collection<?> c) {
        return super.containsAll(c);
    }

    /**
     * Appends all of the elements in the specified Collection to the end of
     * this Vector, in the order that they are returned by the specified
     * Collection's Iterator. The behavior of this operation is undefined if the
     * specified Collection is modified while the operation is in progress.
     * (This implies that the behavior of this call is undefined if the
     * specified Collection is this Vector, and this Vector is nonempty.)
     *
     * @param c elements to be inserted into this Vector.
     * @return <tt>true</tt> if this Vector changed as a result of the call.
     * @throws NullPointerException if the specified collection is null.
     * @since 1.2
     */
    public synchronized boolean addAll(Collection<? extends E> c) {
        modCount++;
        Object[] a = c.toArray();
        int numNew = a.length;
        ensureCapacityHelper(elementCount + numNew);
        System.arraycopy(a, 0, elementData, elementCount, numNew);
        elementCount += numNew;
        return numNew != 0;
    }

    /**
     * Removes from this Vector all of its elements that are contained in the
     * specified Collection.
     *
     * @param c a collection of elements to be removed from the Vector
     * @return true if this Vector changed as a result of the call.
     * @throws NullPointerException if the specified collection is null.
     * @since 1.2
     */
    public synchronized boolean removeAll(Collection<?> c) {
        return super.removeAll(c);
    }

    /**
     * Retains only the elements in this Vector that are contained in the
     * specified Collection. In other words, removes from this Vector all of its
     * elements that are not contained in the specified Collection.
     *
     * @param c a collection of elements to be retained in this Vector (all
     * other elements are removed)
     * @return true if this Vector changed as a result of the call.
     * @throws NullPointerException if the specified collection is null.
     * @since 1.2
     */
    public synchronized boolean retainAll(Collection<?> c) {
        return super.retainAll(c);
    }

    /**
     * Inserts all of the elements in the specified Collection into this Vector
     * at the specified position. Shifts the element currently at that position
     * (if any) and any subsequent elements to the right (increases their
     * indices). The new elements will appear in the Vector in the order that
     * they are returned by the specified Collection's iterator.
     *
     * @param index index at which to insert first element from the specified
     * collection.
     * @param c elements to be inserted into this Vector.
     * @return <tt>true</tt> if this Vector changed as a result of the call.
     * @exception ArrayIndexOutOfBoundsException index out of range (index &lt;
     * 0 || index &gt; size()).
     * @throws NullPointerException if the specified collection is null.
     * @since 1.2
     */
    public synchronized boolean addAll(int index, Collection<? extends E> c) {
        modCount++;
        if (index < 0 || index > elementCount) {
            throw new ArrayIndexOutOfBoundsException(index);
        }

        Object[] a = c.toArray();
        int numNew = a.length;
        ensureCapacityHelper(elementCount + numNew);

        int numMoved = elementCount - index;
        if (numMoved > 0) {
            System.arraycopy(elementData, index, elementData, index + numNew,
                    numMoved);
        }

        System.arraycopy(a, 0, elementData, index, numNew);
        elementCount += numNew;
        return numNew != 0;
    }

    /**
     * Compares the specified Object with this Vector for equality. Returns true
     * if and only if the specified Object is also a List, both Lists have the
     * same size, and all corresponding pairs of elements in the two Lists are
     * <em>equal</em>. (Two elements <code>e1</code> and <code>e2</code> are
     * <em>equal</em> if <code>(e1==null ? e2==null :
     * e1.equals(e2))</code>.) In other words, two Lists are defined to be equal
     * if they contain the same elements in the same order.
     *
     * @param o the Object to be compared for equality with this Vector.
     * @return true if the specified Object is equal to this Vector
     */
    public synchronized boolean equals(Object o) {
        return super.equals(o);
    }

    /**
     * Returns the hash code value for this Vector.
     */
    public synchronized int hashCode() {
        return super.hashCode();
    }

    /**
     * Returns a string representation of this Vector, containing the String
     * representation of each element.
     */
    public synchronized String toString() {
        return super.toString();
    }

    /**
     * Returns a view of the portion of this List between fromIndex, inclusive,
     * and toIndex, exclusive. (If fromIndex and ToIndex are equal, the returned
     * List is empty.) The returned List is backed by this List, so changes in
     * the returned List are reflected in this List, and vice-versa. The
     * returned List supports all of the optional List operations supported by
     * this List.<p>
     *
     * This method eliminates the need for explicit range operations (of the
     * sort that commonly exist for arrays). Any operation that expects a List
     * can be used as a range operation by operating on a subList view instead
     * of a whole List. For example, the following idiom removes a range of
     * elements from a List:
     * <pre>
     *	    list.subList(from, to).clear();
     * </pre> Similar idioms may be constructed for indexOf and lastIndexOf, and
     * all of the algorithms in the Collections class can be applied to a
     * subList.<p>
     *
     * The semantics of the List returned by this method become undefined if the
     * backing list (i.e., this List) is <i>structurally modified</i> in any way
     * other than via the returned List. (Structural modifications are those
     * that change the size of the List, or otherwise perturb it in such a
     * fashion that iterations in progress may yield incorrect results.)
     *
     * @param fromIndex low endpoint (inclusive) of the subList.
     * @param toIndex high endpoint (exclusive) of the subList.
     * @return a view of the specified range within this List.
     * @throws IndexOutOfBoundsException endpoint index value out of range
     * <code>(fromIndex &lt; 0 || toIndex &gt; size)</code>
     * @throws IllegalArgumentException endpoint indices out of order
     * <code>(fromIndex &gt; toIndex)</code>
     */
    public synchronized List<E> subList(int fromIndex, int toIndex) {
        return Collections.synchronizedList(super.subList(fromIndex, toIndex),
                this);
    }

    /**
     * Removes from this List all of the elements whose index is between
     * fromIndex, inclusive and toIndex, exclusive. Shifts any succeeding
     * elements to the left (reduces their index). This call shortens the
     * ArrayList by (toIndex - fromIndex) elements. (If toIndex==fromIndex, this
     * operation has no effect.)
     *
     * @param fromIndex index of first element to be removed.
     * @param toIndex index after last element to be removed.
     */
//    protected synchronized void removeRange(int fromIndex, int toIndex) {
//	modCount++;
//	int numMoved = elementCount - toIndex;
//        System.arraycopy(elementData, toIndex, elementData, fromIndex,
//                         numMoved);
//
//	// Let gc do its work
//	int newElementCount = elementCount - (toIndex-fromIndex);
//	while (elementCount != newElementCount)
//	    elementData[--elementCount] = null;
//    }
//
//    /**
//     * Save the state of the <tt>Vector</tt> instance to a stream (that
//     * is, serialize it).  This method is present merely for synchronization.
//     * It just calls the default readObject method.
//     */
//    private synchronized void writeObject(java.io.ObjectOutputStream s)
//        throws java.io.IOException
//    {
//	s.defaultWriteObject();
//    }
}
